Pump or motor



I I Sept. 13, 1938. w, ERNST 2,130,298

PUMP 0R MOTOR Filed Sept. 28, 1953 2 Sheets-Sheet l.

, as L.

J3-/ s7- 54L Y l 53 INVENTOR. J51 5'- 5 M MMZ.

ATTORNEYS Patented Sept. 13, 1938 UNITED STATES.

PUMP B MOTOR Walter Ernst, Mount Gilead, Ohio, assign'or, by

mesne assignments, to The Hydraulic Press Corporation, Inc., Wilmington, Dei., a corporation oi Delaware Application September 28, 1933, Serial No. 691,380 3 Claims. 01. 103-161) This invention relates to pumps or motors, and particularly to hydraulic pumps or motors having pistons and crossheads reciprocable in guideways or guide blocks.

One object of my invention is to provide such a pump or motor with a rigid crosshead and a guiding means therefor, having a relatively movable reaction element.

Another object is to provide such a pump or 1 motor having a piston crosshead guide block with an adjustable guide block reaction surface, such being free from the wedging action of twopart crossheads. 1

Another object is to provide such a guide block 15 having a slidable element adapted to cooperate with the piston crosshead in providing a wedgeshaped lubrication film.

Another object is to provide such a rigid construction for the crosshead and an adjustable construction for the guide block that this wedgeshaped lubricant film will be created by the oil being caused to move into the lubricant space by suction rather than to be forced in by compression.

25 Another object is to provide such a guide block with relatively movable elements wherein one reaction element is rockable relative to the rim of the guide block.

Another object is to provide such a guide block 30 wherein one reaction element is reciprocable arcuately relative to the remainder of the guide block.

Another object is to provide such a guide block wherein the relative motion between the movable 35 elements is limited by a limiting means provided for that purpose.

Another object is to provide such a guide block wherein successive reciprocations will build up a pressure oil film, a substantial portion of which 40 is renewed at each reciprocation of the 'crosshead.

In the drawings:

Figure 1 is a central horizontal section through a form of pump or motor embodying my inven- 45 tion.

line 2-2 of Figure 1.

Figure 3 is a side elevation 01! the piston, crosshead and guide block assembly employed in my 50 pump or motor.

Figure 4 is a central longitudinal section through the piston, crosshead and guide block assembly shown in Figure 3. l

Figure 5 is across section along the line 5-5 55 of Figure 4.

Figure 2 is a vertical cross section along the Figure 6 is a diagrammatic view of the piston, crosshead and guide block assembly, showing the relative positions of the parts near the end of a stroke in one direction.

Figure 7 is a diagrammatic view similar to Fig- 6 ure 6, but showing the position of the parts near the end of an additional stroke in the opposite direction.

Figure 8 is a graphical representation of the approximate increase in the oil pressure film between the crosshead and the guide block as the crosshead speed varies in its reciprocation.

Referring to the drawings in detail, Figures 1 and 2 show my improved pump or motor having a cylindrical casing i equipped with a supporting base 2, upper and lower slide guide pads 3, and bosses 4 oppositely disposed to one another on a cross diameter and having apertures 5 adapted to receive the shifter rods 6 provided for shifting the secondary rotor 01' the machine to and fro. The casing l is additionally provided with tangential bores I giving access to the interior' portions of the pump, and closed by the threaded plugs 8. A drain port 9 is located in the lower portion of the casing I. The casing I is closed at its ends by the end plates l0 and II having centering shoulders l2. The end plates l0 and :l are secured to the casing ring I by the bolts In each end plate Ill or II is a recess I 4 adapted 39 to receive the outer race l5 of an annular multiple-element bearing. The end plate "I is provided with a hub extension IS in which the enlarged head I1 01. the valve pintle I8 is secured in any desirable way, as by a key. The hub extension I6 is bored transversely with the combined intake and exhaust ports I8 and 20, these communicating respectively with the pintle cutouts 2|, which in turn lead into the upper and lower pairs of combined inlet and outlet passages 22 and 23 respectively.

The pintle l8 projects inwardly from its anchorage in the hub extension it into the pump chamber enclosed between the casing ring I and the end plates l0 and II. The inlet and exhaust passages 22 and 23 in the pintle I8 lead outward into upper and lower valve cut-outs 24 and 2! respectively. The portion of the pintle lying between these valve cut-outs 24 and 25 provides a pintle bridge 26.

The end plate II is equipped with a bearing 21 through which passes the drive shaft 28 terminating in an enlarged head 29. The cylinder barrel or primary rotor 30 is axially bored to receive this enlarged head 28 and counterbored as at Ii to rotatably surround the portion of the pintle II which projects into the pump casing, thus forming an abutment shoulder I2 against which the enlarged head I. is fixedly held by the threaded clamp ring 33. (Figure l.) The drive shaft 2| and the cylinder barrel II are drivingly connected to one another, as by the key 34.

The cylinder barrel or primary rotor 30 has reduced ends adapted to receive the inner races 35 which cooperate with the outer races I 5 in providing annular support for the multiple rotatable bearing elements 36, ball bearings in this case being shown. The cylinder barrel 30 is centrally provided with a plurality of radial cylinder bores 31 having outlets ports 38 communicating with the mntle valve cut-outs 24 and 25.

My machine is equipped with a secondary rotor shifter ring 35, in the periphery of which the secondary rotor shifter rods 5 find threaded seats 4i. (Figure 2.) The shifter ring 39 is provided with guide pads 40 adapted to engage the opposing guide pads I of the casing ring -i. The shifter ring 39 is provided with annular recesses 42 at its sides, these recesses receiving shoulder rings 43 held in place by the set screws 44 and having keeper flanges 45 adapted to hold the outer races 46 of the annular multiple-element bearings.

Encircled by the secondary rotor shifter ring 39 is the secondary rotor 41 in the form of two ring-like half units. These secondary rotor halves 41 have annular recesses 48 and also have laterally extending flanges 49, the latter serving to support the -innerraces 50 opposed to the outer races 46 of the multiple-element bearings 5|. In this way the secondary rotor halves 41 are free to rotate relative to the secondary rotor shifter ring 39 on the anti-friction bearings 5|.

The secondary rotor halves 41 face one another, and between them are mounted the piston crcsshead guide blocks 52 provided with arcuate ribs 53 which fit the annular recesses 48 of the secondary rotor halves 41. Each guide block 52 is provided-with tangentially disposed grooveways 54 in which reciprocate the crossheads 51 of the pistons 56. The latter are radially reciprocable in the cylinder bores 31 of the primary rotor 30, where as the crossheads 51 thereof are tangentially reciprocable in the grooveways 54 of the crosshead guide blocks 52. The secondary rotor grooveways 48 and the guide block ribs 53 are in concentric arrangement with the axis of rotation of the secondary rotor halves 41, thus providing primary reaction surface concentric therewith. This concentricity of the ribs 53 is preferably attained by initially turning a laterally shouldered ring containing all of the guide blocks, this ring being then severed into guide block portions by radial saw-cuts.

The guide blocks 52 are clamped between the secondary rotor halves 41 by means of the clamp .bolts 58 passing through the spacing members 52 which serve to hold and space the guide blocks 52 apart from one another. These spacing members 52 are in the form of keystones, thus positively securing the guide blocks 52 against end play.

Surrounding the secondary rotor halves 41 and secured thereto by the set screws II is a lubricant retaining shell 60 which encloses the guide blocks 52 and thereby impounds lubricant for the latter.

The guide blocks 52 are provided with flat groove-walls 550 (Figure 5) and oppositely disposed secondary reaction surfaces 55, these being arranged concentric with the axis of rotation of the secondary rotor halves 41. Engaging these secondary reaction surfaces 55 are the tilting guide block pads 58 consisting, of elongated bodies having outer cylindrically curved surfaces 64 and inner'flat tertiary reaction surfaces I! normally lying in a tangential direction to the secondary rotor halves 41, and substantially parallel to the inner tangential shoulders of the tangential grooveways 54.

The tilting guide block pads 53 are adap ed to slide relatively'to the secondary reaction surface 55, the guide block pad surface 84 being formed with a corresponding curvature to obtain this result. The tilting guide block pads 53 are additionally provided with 68, enabling a limited amount of arcuate reciprocation of the guide block pads 03 relative to the guide block surface 55, this reciprocation being limited by the pin 61 having the threaded seat 88 in the outer flange of the guide block 52.

In the operation of my machine as a pump, with the primary and secondary rotors It and 41 ,arranged with their axes of rotation coinciding in their neutral positions (Figures 1 and 2), no reciprocation of the pistons 55 and the crossheads 51 will occur when power is applied to the drive shaft 28. When the secondary rotor 41 is shifted so as to place its axis of rotation eccentric relative to the axis of rotation of the primary rotor 30, and power is applied to the drive shaft 28, both the primary and the secondary rotors 30 and 41 respectively will rotate relative to one another around independent axes, because they are operatively coupled together through the piston 56, the crosshead 51 and the grooved guide blocks 52. This eccentric relative rotation will create a variation in the radial distance of the guide block grooves 54 from the axis of rotation of the primary rotor 30, hence, will cause the pistons 56 to reciprocate radially in the cylinder bores 31 and at the same time the piston crossheads 51 will reciprocate tangentially in the guide block grooveways 54. The amount of reciprocation obtained will vary according to the amount of separation of the axes of rotation of the primary and secondary rotors 30 and 41.

As each crosshead 51 thus reciprocates in its grooveway 54, it engages the reaction surface 55 opposed to it on the sliding guide block pad 83, causing the latter to reciprocate slightly in an arcuate path. This action results in the formatherein by reason of its inertia, viscosity and surface tension, and more oil will be provided therein by the additional suction created as the guide block pad 63 reciprocates in the opposite direction. (Figure 7.) Thus in successive reciprocations, the pressure of the oil iilm in the lubricant space 5! becomes built up and maintains a constant layer of lubrication between the relatively reciproca ng reaction surface 65 and the crosshead 51.

i The speed of the crosshead 51 varies approximately according to simple harmonic motion, reaching a minimum of zero at each limit of reciprocation, and a maximum in the middle of its stroke. 'Ihe pressure of the oil illm built up in the space 69 varies according to this crosshead speed, and reaches a maximum at substantially the midpoint of the stroke where the crosshead speed is a maximum. This relationship between the oil pressure P of the oil film and the crosshead speed S of the crosshead between its limits of reciprocation is shown in Figure 8.

Thus it will be observed that my crossheads 51 are unitary bodies without relatively movable elements, so that no wedging action can occur as a result of one crosshead element with respect to the other. Such accidental tilting is liable to cause a jamming of the crosshead in its grooveway 54, with consequent damage to the pump, as has actually occurred in prior art machines. In my improved construction, however, this danger is entirely eliminated, since the relative tilting between the guide block 51 and the reaction surface opposed to it occurs by reason of the sliding element 63 on the guide block, not by relatively movable elements in the crosshead. Fur thermore, lubricant film in my crosshead and guide block assembly occurs as the result of suction arising in the wedge-shaped space formed between the crosshead and slidable guide block pad 63, this space opening backwardly from the direction of reciprocation, rather than by compression in a wedge space with its opening forwardly in the direction of reciprocation.

While I have shown my improved guide block and crosshead as applied to a radial type of hydraulic machine, it will be understood that this same construction is also applicable to those types of hydraulic pump or motor having the cylinders arranged either parallel or tangential to the axis of rotation of the drive shaft 28.

It will be understood that I desire to comprehend within my invention such modifications as may be necessary to adapt it to varying condi-' tions and uses.

It will also be understood that it may. occasionally be found desirable to curve the ends of the sliding guide block pad 65 in order to facilitate their arcuate reciprocation, and that such a modiflcation is contemplated and included within the scope of my invention.

Having thus fully described my invention, what- I claim as new and desire to secure by Letters Patent is:

1. In a fluid pressure pump or motor; a hollow guide block member, said member including an arcuate portion having inner and outer arcuate reaction surfaces, and sides integrally connected to said arcuate portion and having guide grooves therein; a reactance rotor embracing the outer arcuate reaction surface of said guide block member, a movable reaction member engaging said inner arcuate reaction surface of said guide block member for reciprocation relatively thereto; and a piston-crosshead mounted for rectilinear reciprocation in said grooves and against said movable reaction member, said movable reaction member being adapted to slide relatively to said guide block member and tilt relatively to said crosshead.

2. In a fluid pressure pump or motor; a hollow guide block member, said member including an arcuate portion having inner and outer arcuate reaction surfaces, and sides integrally connected to said arcuate portion and having guide grooves therein; a reactance rotor embracing the outer arcuate reaction surface of said guide block member, a movable reaction member engaging said inner arcuate reaction surface of said guide block member for reciprocation'relatively thereto; a piston-crosshead mounted for reciprocation in said guide grooves and against said movable reaction member, said movable reaction member being adapted totilt relatively to said crosshead, and means arranged between said reaction member and said guide block member for limiting theamount of reciprocation of said reaction member relatively to said guide block member.

-3.' In a fluid pressure pump or motor; a hollow guide block member, said member including an arcuate portion having inner and outer arcuate reaction surfaces, and sides integrally connected to said arcuate portion and having guide grooves therein; a reactance rotor embracing the outer arcuate reaction surface of said guide block member, a movable reaction member engaging said inner arcuate reaction surface of said guide block member for reciprocation relatively thereto; and a piston-crosshead mounted for reciprocation in said guide grooves and against said movable reaction member, said movable reaction member being adapted to tilt relatively to said crosshead, one of said members having a depression and the other member having a projection engaging said depression for limiting the reciprocation of said reaction member relatively to said guide block member.

WALTER ERNST. 

